Why This Report Matters. Air quality policy in Canada is at a crossroads. Decades of regulation have successfully cut industrial and combustion-related PM2.5, but those gains are increasingly erased by wildfires and urbanization-driven dust. Decision-makers in public health, urban planning, and climate adaptation need to understand which sources are improving, which are worsening, and where the next crisis will come from. This report translates 34 years of federal emissions data into actionable patterns: where to double down on regulation, where to invest in monitoring, and why wildfire smoke policy is now a public health emergency.
Chapter 1 · Background. This report explores three decades of Canada’s fight against fine particulate matter - the most dangerous common air pollutant. Using national inventory data, provincial reports, and city-level monitoring, it asks three questions:
Fine particulate matter (PM2.5) refers to particles smaller than 2.5 micrometres, about 30 times smaller than a human hair. Unlike larger particles that your nose and throat filter out, PM2.5 bypasses your lungs and enters your bloodstream, causing damage far beyond the respiratory system. It is the single largest environmental health risk in Canada.
The data comes from the Air Pollutant Emissions Inventory (APEI) 2025 Report by Environment and Climate Change Canada, which tracks anthropogenic emissions across five PM2.5 source categories. It does not include wildfire emissions in its main totals, a critical distinction explored later.
Chapter 2 · The National Picture. Total anthropogenic PM2.5 fell from roughly 1,609 kt in 1990 to 1,370 kt in 2023 (a 15% decline). But this hides a tug-of-war: industrial and combustion sources have plummeted, while dust from roads and construction has climbed steadily.
All national emissions data comes from the APEI 2025 Report (1990–2023) by ECCC. Provincial data from Ontario’s Air Quality Report 2023. City-level PM2.5 from NAPS and IQAir. All figures are emissions (tonnes) unless labelled as concentrations (µg/m³).
Emissions = how much is released. Concentrations = what people breathe. Weather, geography, and transboundary transport affect the relationship.
Canada’s standard for annual PM2.5 is 8.8 µg/m³. The WHO recommends 5 µg/m³. No major Canadian city meets the WHO guideline.
The APEI 2025 report (published March 2025) covers through 2023. This ~2 year compilation lag is standard for government inventories worldwide.
National emissions were transcribed from APEI 2025, Chapter 2.1,
Table 2-3. Area burned data compiled from the National Forestry Database
and CNFDB. City PM2.5 concentrations (2014–2022) compiled from NAPS
annual summaries and provincial air quality reports; 2023 values from
the IQAir World Air Quality Report. Wildfire PM2.5 estimates derived by
multiplying area burned by an emission factor of ~713 kt/Mha (ECCC/UNDRR
methodology). National average concentrations from ECCC’s CESI air
quality indicators. The prepare_data.R script documents all
sources and can read directly from raw ECCC data files when
available.
APEI data is national/provincial only. City data uses ambient monitoring mixing local, regional, and transboundary sources. IQAir 2023 values include low-cost sensors.
Analysis by Nooran Abu Mazen · Data: ECCC (APEI 2025), Ontario Ministry of the Environment, NAPS, IQAir · Built with R flexdashboard & Plotly